Compounds of the triphenyltin(II) ion

Ionic compounds R+SnPh3-, where R = Me4N, (Ph3P)2N, Na(15-crown-5) or K(18-crown-6), are prepared from alkali metal derivatives, Ph3SnM, by reactions in liquid ammonia which yield the products as yellow crystalline solids, soluble in a weakly basic solvent. N.m.r. and vibrational spectra of the Ph3Sn- anion, a pyramidal species with C3V symmetry, and the cationic complexes [M(crown)]+, are reported and assigned.

Multiple congenital anomalies, thymic dysplasia, severe congenital heart disease, and oligosyndactyly with a deletion of the short arm of chromosome 5

A female infant was born at term with congenital anomalies and a deletion of the short arm of chromosome 5. The anomalies included thymic dysplasia and lymphocyte-depleted nodes of the type seen in combined immune deficiency; atrial and ventricular septal defects, pulmonary valve atresia, and anomalous pulmonary-bronchial communication through the lungs; and shortness of forearms with syndactyly of fingers. A review indicates that the association of cardiac lesions, thymic dysplasia, oligosyndactyly and deletion of chromosome 5p is unique.

Antioxidant activity of skim milk: effect of sonication

The antioxidant activity of skim milk was evaluated in a linoleate emulsion system with hemoglobin as a pro-oxidant. Sonication greatly increased the antioxidant activity of skim milk. The antioxidant activity of the casein fraction of milk was increased most by sonication, and this increase was nearly as great as that for skim milk, suggesting that casein was almost totally responsible for the antioxidant effect of sonication. Total sulfhydryl groups of skim milk decreased upon prolonged sonication, probably the result of the heat evolved in the process. Reactive sulfhydryl content was unchanged by sonication. Sonication had no effect on antioxidant activity of beta-lactoglobulin, reduced urease, or reduced ribonuclease, proteins with free sulfhydryl groups. Apparently sulfhydryl groups were not involved in the increased antioxidant activity of sonicated skim milk. Homogenization at 281.5 kg/cm2 did not increase the antioxidant effect of skim milk. Sonication probably disrupted casein micelles, increasing the effective concentration of casein, which could account for the increased antioxidant activity in the system.

An information-retrieval system for classifying work in the field of cerebral asymmetry

A hierarchically-branching system is recommended for classifying published work in the field of cerebral asymmetry, and its rapid retrieval. It can readily accommodate partically everything published since 1965.

An Information-Retrieval System for Classifying Work in the Field of Cerebral Asymmetry

A hierarchically-branching system is recommended for classifying published work in the field of cerebral asymmetry, and its rapid retrieval. It can readily accommodate practically everything published since 1965.

Concentrations of placental lactogen in chronically catheterized ewes and fetuses in late pregnancy

The concentration of ovine placental lactogen (oPL) was measured by radioimmunoassay in plasma samples from chronically catheterized ewes and their fetuses from day 110 of gestation to term (about day 145). Concentrations of oPL in the plasma of the mother and fetus were raised after surgery, and remained raised for 3--5 days after the operation. Concentrations of oPL were greatest in the fetus at days 120--124 of gestation, and then declined until delivery. Mean concentrations of oPL in the fetus in late pregnancy for single, twin and triplet pregnancies were 101 +/- 6 (S.E.M.), 100 +/- 11 and 115 +/- 59 ng/ml respectively and were not significantly different. Mean concentrations of oPL in the mother in late pregnancy for single, twin and triplet pregnancies were 718 +/- 227, 1387 +/- 160 and 1510 +/- 459 ng/ml respectively; the difference between these means was significant (P less than 0.05). Peak concentrations were noted at days 130--139 of gestation after which concentrations fell and were significantly lower on the day of delivery (P less than 0.01). Concentration of oPL in the mother showed no circadian rhythm. The mean concentrations of oPL in maternal plasma during late pregnancy was significantly correlated to the combined fetal weight at birth (r = 0.624, P less than 0.01).

Vibrational spectra of complexes of mercury(I) and mercury(II) with pyridine and other nitrogen bases

Raman and i.r. spectra of the series of compounds MeHg(pyx)ClO4, Hg(pyx)n(ClO4)2 and Hg2- (pyx)n(ClO4)2 (pyx = pyridine or a pyridine derivative; n = 2 or in some cases 4) are reported. In the low- frequency region, the spectra of the complex cations provide the basis of assignments of Hg-N (160-260 cm-1) and Hg-Hg (110-160 cm-1) stretching frequencies.

Vibrational spectra of adducts of iodine monochloride with some pyridine bases

A series of molecular adducts, L-ICl, where L = pyridine or a pyridine derivative, have been prepared and the solid state spectra examined by Raman and far-infrared spectroscopy. Assignments of the modes v(I-Cl) 240-300 cm-1 and v(N-I) 90-180 cm-1 and force constant calculations on a simple three-centre model yield information on structure and bonding related to the nature of the pyridine donor. Several ionic products containing the Icl2- ion have been encountered.

Partial purification and characterization of a ribonucleic acid N2-guanine methyltransferase associated with avian myeloblastosis virus

A nucleic acid methylase, N2-guanine ribonucleic acid (RNA) methyltransferase, which is associated with type C RNA tumor viruses, has been purified from avian myeloblastosis virions by gel filtration on Sephadex G-200, followed by chromatography on hydroxylapatite. The molecular weight estimated by gel filtration is 220 000, and the methylase activity has a pH optimum of 7.6--7.9. Magnesium and ammonium ions both stimulate activity 1.5-fold at 9.5 mM and 0.36 M, respectively, but apparently neither is essential for activity. Both daunomycin and adriamycin, antineoplastic drugs, also increase activity 1.5-fold at 1 mM. The enzyme was purified 120-fold from the virions and the activity is partially stabilized by dithiothretiol, but large losses were sustained during 24-h dialysis. The purified enzyme retains 75% of its activity on storage at -25 degrees C for 2 months in buffer containing 50% glycerol. Escherichia coli tRNAPhe and tRNAVal are preferred substrates with methylation occurring at position 10 of E. coli tRNAPhe.

Bereitschaftspontential during the acquisition of a skilled motor task

Bereitschaftspontential (BP) research typically uses very simple, abrupt movements that require no learning and which change little over the duration of the experimental session. The present study investigated changes in the size and cortical distribution of the BP during the acquisition of a skilled motor task. Twelve subjects were employed. Electrodes at FZ, CZ, C3'' and C4'' were used to record the EEG with DC amplifiers. A series of 6 button presses in a specified pattern constituted the motor task. Subjects were instructed to press the series every 20 sec as quickly as possible, but with no errors. Significant response time, electrode and trial main effects, and electrode by trial interactions were found. The BP increased steadily at all electrodes as performance improved, i.e., as response time decreased. After the response reached asymptote the BP recorded at FZ and C4'' decreased, while the BP at CZ and C3'' remained relatively constant. Multivariate analyses of covariance showed a consistent relationship between the improvement in response times and the changes in the BP. This study demonstrates that the size and cortical distribution of the BP are systematically related to improved proficiency of a motor response with learning.

The response of the glass/calomel pH-cell in aqueous solutions containing dimethylsulphoxide at 25 and-12 degrees C

For 4 months, a prototype digital subtraction system was used to obtain images of the cerebral vasculature after intraarterial contrast injections. In 12 instances, the intraarterial injections were recorded with both a digital subtraction unit and conventional direct magnification film-screen system. The digital subtraction and conventional film subtraction images were compared and graded for quality and information content by three skilled observers. In addition, quantitative measurements of contrast-detail performance and spatial resolution were obtained on both the digital system and the screen-film imaging chain. In a clinical setting, both the digital subtraction and conventional film-screen systems provided similar quality images and angiographic information. Contrast-detail curves demonstrated that digital subtraction angiography outperformed conventional film technique for low-contrast objects. Digital subtraction angiography also reduced the time required to obtain the angiogram, markedly reduced film cost, and lowered the contrast agent burden.

Pulsed CO(2) TEA laser rangefinder

A compact laser rangefinder has been developed, which incorporates a sealed-off pulsed CO(2) TEA laser and uses direct (i.e., nonheterodyne) detection. This device is essentially eye safe and benefits from the superior atmospheric transmission at 10.6-microm wavelength. Design parameters are presented and illustrated, and system performance is discussed.

Vibrational spectra of mercury(I) nitrate in aqueous solution and of the crystalline hydrolysis products

Aqueous solutions of 'mercurous nitrate' are shown by Raman spectra to contain the complexes [Hg2(OH2)NO3]+ and [Hg2(OH2)2]2+. Crystalline dimercury(I) nitrate, Hg2(NO3)2,2H2O, and its solid hydrolysis products Hg2(OH)2,3Hg2(NO3)2, 2Hg2(OH)2,3Hg2(NO3)2,H2O and Hg2(OH)2,- Hg2(NO3)2 have been obtained: the vibrational spectra are reported and interpreted in terms of possible structures. Modes v(Hg-Hg) appear in the range 170- 200 cm-1 and are sensitive to the particular combination of the ligands OH, ONO2, and H2O attached to the dimercury(I) ion.